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Helioseismology from the South Pole: Results from the 1987 campaign

  • S. M. Jefferies
  • T. L. DuvallJr.
  • J. W. Harvey
  • M. A. Pomerantz
Part IV Observations of Solar Oscillations
Part of the Lecture Notes in Physics book series (LNP, volume 367)

Abstract

This paper presents some results on the frequencies and line widths of features in solar p-mode spectra obtained from 460 hours of observations made at South Pole in 1987. To investigate the possibility of temporal variations in these quantities, a comparison is made with measurements obtained from data taken in 1981. The differences between the frequencies measured from the 1981 and 1987 data sets appear to be independent of both frequency (2.4 ≤ v ≤ 4.8 mHz) and degree (3 ≤ ℓ ≤ 98). The mean difference (v1981v1987) averaged. over v and ℓ is found to be 224 ± 19 nl1z. The line width measurements display the same variation with v as that previously reported (Libbrecht 1988a), an increase with ℓ (Duvall et ad. 1988) and with solar activity. Measurement of the rotational splittings of sectoral modes (m = ±ℓ) in the range (3 ≤ ℓ ≤ 15), shows no indication of a dependence on the depth of the lower turning points of these modes.

Keywords

Solar Activity Line Width High Solar Activity Spherical Harmonic Coefficient Sectoral Mode 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • S. M. Jefferies
    • 1
  • T. L. DuvallJr.
    • 2
  • J. W. Harvey
    • 3
  • M. A. Pomerantz
    • 1
  1. 1.Bartol Research InstituteUniversity of DelawareNewarkUSA
  2. 2.Laboratory for Astronomy and Solar PhysicsNASA/Goddard Space Flight CenterGreenbeltUSA
  3. 3.National Solar ObservatoryNational Optical Astronomy ObservatoriesTucsonUSA

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